Print reader comprising two mutually orthogonal scanning slits and a drum having a light transmissive surface

ABSTRACT

An apparatus is disclosed for converting printed material of any typefont into electrical signals suitable for conversion and use with a digital computer. Light transparent paper, with light impervious printed matter thereon, is placed on a roll and illuminated uniformly from within such roll. The page is scanned on a line to line basis by rotating the roll intermittently, and on a character by character basis by a motor driven tape carrying a light slit. The resulting light signal is converted into an analog electric signal representative of the scanned print, which can be converted to digital form for use in electronic data processing equipment.

United States Patent William J. Rifle R.R. #2, Short Line Pike, Berea, Ky. 40403 [2]] Appl. No. 822,155

[22] Filed May 6, 1969 [45] Patented May 4, 1971 [72] Inventor [54] PRINT READER COMPRISING TWO MUTUALLY ORTHOGONAL SCANNING SLITS AND A DRUM HAVING A LIGHT TRANSMISSIVE SURFACE 3 Claims, 3 Drawing Figs.

[51 Int. Cl G0ln 21/30,

l-lOlj 3/14,H01j 5/02 [50] Field ofSearch 250/219 (ICR), 219 (Wd), 237, 219 (IA), 239

[56] References Cited UNITED STATES PATENTS 2,937,283 5/1960 Oliver 250/219XICR Primary Examiner-Jones W. Lawrence Assistant Examiner-T. N. Grigsby Att0rneyPaul & Paul ABSTRACT: An apparatus is disclosed for converting printed material of any typefont into electrical signals suitable for conversion and use with a digital computer. Light transparent paper, with light impervious printed matter thereon, is placed on a roll and illuminated uniformly from within such roll. The page is scanned on a line to line basis by rotating the roll intermittently, and on a character by character basis by a motor driven tape carrying a light slit. The resulting light signal is converted into an analog electric signal representative of the scanned print, which can be converted to digital form for use in electronic data processing equipment.

Pmmn'zum 4 maaana 330mm INVENTOR. William J. Riffe ATTORNEYS.

vantages of the prior art.

PRINT READER COMPRISING TWO MUTUALLY ORTIIOGONAL SCANNING SLITS AND A DRUM-HAVING A LIGHT TRANSMISSIVE SURFACE BACKGROUND OF THE INVENTION l. Field of the Invention This invention relates to optical scanning apparatus, and in particular to an apparatus for convening typed data into electri'cal signals suitable for utilization in electronic data processing equipment.

2. Description of the Prior Art The electronic data processing industry has grown very rapidly in the last decade. Basic main frame computer hardware has passed through a succession of three generations, and provides data processing at exceedingly high speeds. However, the peripheral equipment required to feed information into and out of such computers has not maintained the same development pace. In particular, most computer systems are fully automated except for the step of translating written information onto magnetic tape, paper tape, punched paper cards, or other forms of offline data storage. To meet this need, a number of manufacturing companies have developed large optical scanners for use with digital computers. However, such scanners are exceedingly complex and expensive, generally costing in excess of $100,000. In addition, they do not provide the flexibility of operation desired, particularly for smaller volume users. In operation of these machines, the user must prepare his written data on specially preparedforms, and is limited in the kind of information which can be placed on suchforms. Consequently, there remains a need for a lowpriced, simple device, having a flexibility of being able to read directly from the printed material as it comes to the user, and not requiring the user to purchase or maintain high cost equipment which can be afiorded only by large sized industrial firms.

SUMMARY OF THE INVENTION The primary object of my invention is to provide apparatus for automatically converting typed information into electrical signals suitable for conversion and use in digital computers.

It is a further object of my invention to provide apparatus for conversion of typed information into electrical signals which is simple, easy to operate, lightweight, inexpensive and effective for the purpose and which overcomes the disad- Accordingly, this invention provides a novel and effective apparatus for converting printed information into electrical signals. This highly desirable result is achieved by transposing the printed information onto light transparent paper, with the print being light impervious. The printed page is mounted for rotation on a drum driven by a controllable motor, having mounted within, and onathe center axis thereof, a light source providing uniform illumination to the interior surface of the paper. Positioned adjacent to the exterior cylindrical surface is the elongated rectangular edge of a light channel, which edge contains a narrow slit running the length thereof, which is positioned opposite a given line of type. Said light channel also has a photoelectric device at the other end thereof. An opaque tape having a slit juxtaposed vertically with respect to the horizontal rectangular end of the light channel is drawn at a constant speed across said rectangular end of the light channel, thus causing an optical signal to be traced representative of the letters of the given line which have been scanned by the vertical light slit. This optical signal is sensed by the photoelectric device, which converts same into an analog electrical signal representing the information of the line the cylinder is rotated one line, and the following line is scanned. In this manner, a complete page of information is translated into corresponding electrical signals.

scanned. After scanning a line, the tape is returned to the left,

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a simplified diagrammatic perspective representation of a print reader for converting the information contained on a printed sheet into representative analog electrical signals.

FIG. 2 is a diagrammatic representation of a tape with a vertical slit which scans the characters.

FIG. 3 is a diagrammatic representation of the electrical analog signal generated by scanning the letter t.

DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 illustrates diagrammatically the apparatus provided in accordance with the present invention for converting printed data on light transparent paper directly into electrical signals, without any intervening manual or human operations.

A cylinder or drum 20 of transparent material is mounted for rotation on a shaft 21 driven by a controlled motor 22.

Mounted within the transparent drum 20 on the center axis thereof, is an elongated light source 23, such as a fluorescent lamp, for providing uniform illumination to the interior surface of the drum 20. Means, not shown, are provided for removably securing the printed page 12 to the circumferential surface of the drum.

Positioned adjacent to the exterior cylindrical surface of the transparent drum 20 is an elongated rectangular edge 31 of a light channel box 30. Box 30 has a rectangular configuration at edge 31, but has a cylindrical configuration at the other edge 32. The elongated rectangular edge 31 of the light channel box 30 is provided with a long narrow scanning slit 37 which is adjustable in width. Scanning slit 37 carries a width substantially identical to the height of the characters in the typefont being scanned. Consequently, with drum 20 in a given position, scanning slit 37 will face a given line of typefont on the paper which is wrapped around the drum.

Referring now to FIG. 2, it is seen that within the elongated rectangular edge 31 of the light channel box 30 is a vertical opening 50 running the length of edge 31. Within vertical opening 50 is mounteda tape 51 constructed of a light impervious material. Said tape 51 fits within vertical opening 50 with very close tolerances, such that no appreciable light passes out of the light channel box 30. Said tape is coiled around and mounted on two cylindrical pulleys 61 and 62. Pulley 61 is driven by constant speed motor means 63, whereby to pull the tape longitudinally across scanning slit 37. Cylindrical pulley 62 contains return spring means whereby to return the tape to position for rescanning. In this configuration, with extremely small tolerances between the drum surface 20 and the light channel box 30, and also with small tolerances between the tape 51 and the vertical opening 50, there is no appreciable light leakage out of the light channel box.

The tape contains a vertically aligned light slit 52, having a width which is a small fraction of the width of a character of the typefont being scanned. At the start of a scan of a line, said light slit is located at the left of the page 12. The tape scans transversely, along the longitudinal axis of the transparent drum 20, being driven by constant speed means 63. When the tape has thus been drawn, at a uniform rate, across the elongated rectangular edge 31 such that the light slit 52 reaches the right side of page 12, motor means 63 is released and the tape 51 is caused to return to the left by the return spring means located within pulley cylinder 62, in position to scan the next page.

' It is thus seen that only at the point of slit 52 will there be transmission of light from the inside of transparent drum 20, the light passing through the transparent paper, the scanning slit 37, and slit 52. It is thus seen that the light which does get through slit 52 at any given instant of time will be determined by the precise configuration of the character of type which faces slit 52. lnsomuch as slit 52 is of a width narrower than that of a given character of typefont, at any given time only one character will affect the light which passes through and is collected in light channel box 30.

,' Mounted within the light channel box 30 at the cylindrical end 32 is a light-gathering lens 33, and inserted into the open cylindrical end 32 of the box 30 is a cylindrical casing having therein a photocell 35. A lead 36 leads to a suitable known form of amplifier.

it will be understood that the quantity of current developed by the photocell 35 is a function of and proportional to the quantity of light falling thereon, and that the quantity of light falling thereon is in turn a function of and proportional to the amount of light from source 23 which passes through both slit 37 and slit 52. Such quantity of light is a function of the lightimpervious printed character being scanned simultaneously by both slit 37 and slit 52.

The term sensitivity," as used in this application, refers to the capability of the apparatus to read the variations in light due to the character being scanned. Assuming that sufficient light can be made available to the photocell 35, the sensitivity of the apparatus will be optimized when the width of slit 37 just equals the height of the characters of the line being scanned. To allow the user to control this sensitivity so that it is in the optimal range for the best function of the photocell 35, and for best resolution of the characters being scanned, the scanning slit 37 is adjustable in width. Similarly, the user will choose a tape 51 having a vertical slit 52 with a width much narrower than the width of the characters in the typefont being scanned. Thus, my invention embraces flexibility for scanning any type of typefont.

The operation ofthe print reader can be seen from an inspection of HO. 3. FIG. 3 shows a perspective view of the tape 51, scanning slit 37, and vertical slit 52. Slit 52, scanning from left to right in FIG. 3, is shown as having just intercepted the cross portion of the letter 1. As slit 52 scans across the letter 1, the amount of light passing through such slit will be a function of the amount of light which is blocked by the opaque portions of the letter t. It is seen that before the slit intercepts the cross of the t, at point A, the photocell current is constant and at a maximum value. When the slit intercepts the cross portion of the t, at point B, the current drops somewhat due to the opaque portion of the letter. As the slit intercepts the vertical portion of the t, at point C, a maximum amount of light is blocked from passing through slit 52, and the resulting photocell current drops to a minimum. As the slit progresses beyond'the vertical portion, the photocell current rises to a level D, at which level the light is blocked both by the cross of the t and the lower-portion thereof. As the slit passes beyond the letter i, at point E, the photocell current returns to its maximum value. The current thus traced out, as shown in FIG. 3, is unique for the letter I, and in particular, for this typefont of the letter 1. Other letters of the same typefont would result in singular current waveforms being generated, and similarly, each typefont would produce a singular waveform representative of each character in the typefont.

The analog current waveform as shown in FIG. 3 represents when the tape is being returned for scannin of.the next line.

l have illustrated and described in simp ified diagrammatic form a preferred form of apparatus for carrying out the steps of the method of the present invention. While the preferred embodiment of this invention has been described in some detail, it will be obvious to one skilled in the art that various the translation of the information from the printed page to an electrical signal. The analog signal can be processed and placed into pulse form by special purpose computers which are designed for this purpose, and which are commercially available. Thus, the procedure of translating the printed page into electrical signal form suitable for data processing can, with the use of the print reader of this invention, be accomplished in an entirely automated manner, and without any intervening human operation.

Where, as contemplated, the printed characters detected are to be translated into signals which are to be fed directly into a computer, the tape is driven at a speed such that the signals generated by the photocell 35 are produced at a rate which corresponds to that which is acceptable by such computer. During the time period that the tape is returning to scan a new line, motor 22 is energized to turn drum 20 to the next line, whereupon scanning will be repeated. Suitable control circuitry can be adapted such that the computer will know modifications may be made without departing from the invention as hereinafter claimed.

lclaim:

l. A method of generating electrical signals representing alphanumerical characters, comprising the steps of:

a. placing printed character information, in the form of light-impervious alphanumerical characters, on a lighttransparent sheet, said characters being positioned in equally spaced rows and being spaced in each row such that no character overlaps another;

b. placing said sheet on a hollow elongate drum with a lighttransparent surface, and illuminating uniformly the rear surface of said sheet from within said elongate drum;

c. positioning a row-scanning slit in registry with a given row of said sheet;

d. moving a character-scanning slit, held normal to said row-scanning slit, across said given row, from a beginning row position to an ending row position, thereby generating analog light signals representing respectively each of said characters in said given row; e. converting said analog light signals into electrical signals;

and concurrently returning said character scanning slit to said beginning row position and positioning said row-scanning I slit in registry with a next row of said sheet, for scanning of said next row.

2. The method as described in claim 1 wherein said rowscanning slit is positioned in registry with said next row of said sheet by rotating said drum.

3. Apparatus for converting printed character information into corresponding electrical signals comprising:

a. printed sheet means, said means being light-transparent and having printed thereon light-impervious alphanumerical characters, for providing alphanumeric characters positioned in equally spaced rows, such characters being spaced in each row such that no character overlaps another;

b. rotatable drum means for carrying said sheet means;

c. illumination means mounted axially throughout the length of said drum means, for illuminating uniformly the rear surface of said sheet means;

d. a light-tight box having an elongated rectangular edge, said edge being aligned in parallel with the axis of said drum and positioned contiguous to and in closerelationship with the surface of said drum, and such edge having, in parallel with said axis, a row-scanning slit of a length greater than said character rows and a width approximately equal to the height of said characters;

e. said rectangular edge having opening means therein normal to said row-scanning slit for movably positioning a character-scanning slit, said character-scanning slit being oriented normal to said row-scanning slit and movable the length of said row-scanning slit, and having a length approximately equal to the height of said characters and a width which is a fraction of the width of said characters;

f. means for providing relative motion between said printed sheet means and said row-scanning slit;

g. lens means located in said light tight box at the rearward end thereof for gathering light passing through both rowscanning means and said character scanning means; and

h. photosensitive means at the rearward end of said box for detecting the analog light signals transmitted through said lens means and for converting said light signals into corresponding electrical signals. 

1. A method of generating electrical signals representing alphanumerical characters, comprising the steps of: a. placing printed character information, in the form of lightimpervious alphanumerical characters, on a light-transparent sheet, said characters being positioned in equally spaced rows and being spaced in each row such that no character overlaps another; b. placing said sheet on a hollow elongate drum with a lighttransparent surface, and illuminating uniformly the rear surface of said sheet from within said elongate drum; c. positioning a row-scanning slit in registry with a given row of said sheet; d. moving a character-scanning slit, held normal to said rowscanning slit, across said given row, from a beginning row position to an ending row position, thereby generating analog light signals representing respectively each of said characters in said given row; e. converting said analog light signals into electrical signals; and f. concurrently returning said character scanning slit to said beginning row position and positioning said row-scanning slit in registry with a next row of said sheet, for scanning of said next row.
 2. The method as described in claim 1 wherein said row-scanning slit is positioned in registry with said next row of said sheet by rotating said drum.
 3. Apparatus for converting printed character information into corresponding electrical signals comprising: a. printed sheet means, said means being light-transparent and having printed thereon light-impervious alphanumerical characters, for providing alphanumeric characters positioned in equally spaced rows, such characters being spaced in each row such that no character overlaps another; b. rotatable drum means for carrying said sheet means; c. illumination means mounted axially throughout the length of said drum means, for illuminating uniformly the rear surface of said sheet means; d. a light-tight box having an elongated rectanGular edge, said edge being aligned in parallel with the axis of said drum and positioned contiguous to and in close relationship with the surface of said drum, and such edge having, in parallel with said axis, a row-scanning slit of a length greater than said character rows and a width approximately equal to the height of said characters; e. said rectangular edge having opening means therein normal to said row-scanning slit for movably positioning a character-scanning slit, said character-scanning slit being oriented normal to said row-scanning slit and movable the length of said row-scanning slit, and having a length approximately equal to the height of said characters and a width which is a fraction of the width of said characters; f. means for providing relative motion between said printed sheet means and said row-scanning slit; g. lens means located in said light tight box at the rearward end thereof for gathering light passing through both row-scanning means and said character scanning means; and h. photosensitive means at the rearward end of said box for detecting the analog light signals transmitted through said lens means and for converting said light signals into corresponding electrical signals. 